Dyeing spun cellulose derivative staple fibers in alcoholic solutions and then skying



Patented May 15, 1951 UNITED STATES PATENT OFFICE- DYEING SPUN CELLULOSE DERIVATIVE STAPLE FIBERS IN ALCOHOLIC SOLU- TIONS AND THEN SKYING Wilfred T. Normand and William J. Cramer, Jr., a

Cumberland, Md., assignors to Celanese Corporation of America, a corporation of Delaware No Drawing. Application October 7, 1947, Serial No. 778,462

Claims. 1

This invention relates to the dyeing of textile materials and relates more particularly to the dyeing of textile fabrics made of or containing yarns having a basis of cellulose acetate or other organic derivative of cellulose material.

An object of this invention is the provision of an improved process for the dyeing of textile fabrics made of or containing yarns, and particularly, spun yarns of staple fibers, having a basis of cellulose acetate or other organic derivative of cellulose material whereby said fabrics may be dyed in even, level shades free of overdyed surface fibers.

Another object of this invention is to provide an improved process for the dyeing of cellulose acetate or other organic derivative of cellulose fabric .materials wherein improved dyeing efliciency and increased color value is obtained.

Other objects of this invention will appear from the following detailed description.

In the dyeing of textile materials, such as fabrics, the latter are firstscoured to remove the weaving size present as well as any yarn lubricating or conditioning agent and the scoured fabric then entered into the dyebath employed. When dyeing fabrics woven of yarns having a basis of cellulose acetate or other organic derivative of cellulose textile material, it has been observed that these materials are dyed more slowly than other textile materials since they are less absorbent and the aqueous dyebaths usually employed do not penetrate said materials as rapidly or as completely as in the case of other textile materials. Accordingly, various organic and inorganic materials have been employed in conjunction with water to form modified solvent dyebaths of increased penetrating action so as to enable the desired dyeing to be effected more rapidly. Among the most effective dyebaths which have been employed are aqueous solutions of lower aliphatic alcohols, such as ethyl alcohol, containing a salt of thiocyanic acid which is a swelling agent for said cellulose acetate or other organic derivative of cellulose materials. Dyebaths comprising said lower aliphatic alcohols and swelling agents are preferably applied to fabrics by padding operations, the dyed fabrics scoured to remove excess dyestuff and the fabrics then dried and finished. While reasonably rapid, commercially satisfactory dyeings are usually obtained when cellulose acetate or other organic derivative of cellulose fabric materials are dyed in the manner described above, increased dyeing efficiency and more rapid dyeing methods have been continuously sought. Furthermore, it has 2 y been observed that where fabrics woven gof-or containing spun yarns of staple fibers having-a basis of cellulose acetate or other organic deriva tive of cellulose material are scoured and'dyed; as described, the staple fiber ends which project from the surface of the fabric are dyed in a considerably deeper shade than the main body of the fabrics, yielding a fabric ofanunevenly; dyed, mottled appearance. 1

We have now found that cellulose acetate-or other organic derivative of cellulose textile mate; rials, such as fabrics, may be dyed very rapidly and in even, level shades free of overdyed. surface fibers by mechanical impregnation methods-such as pad-dyeing, if the dyebath employed consists of a dyestuff or mixture of dyestuffsfor said cellulose acetate or other organic'derivativewof cellulose textile material in solution'in a concentrated lower aliphatic alcohol preferably containing from 0 to 5% by weight of water as the sole components of-said dyebath,-thelatter being free of inorganic swelling agents for the cellulose acetate or other organic derivative of cellulose material being dyed. Thus, in the caseof ethyl alcohol, we preferably employ a by weight solution of ethyl alcohol as the liquid medium comprising the dyebath. While absolute alcohol may be employed, reasons of economy Prohibit its use. By employing such concentrated alcohol solutions, we have found that inorganic swelling agents are unnecessary and the dyed fabrics-need not be actually scoured after dyeing toremove excess dyestuif prior to finishing, r In accordance with our novel process, the fab rics are pad-dyed with said concentrated alcohol dyebath, the dyed fabrics then allowed to dry by skying the fabric over rolls to effect the evaporationof the alcohol of the dyebath and the dry, dyed fabrics then merely rinsed in water-prior to finishing. The recovery of the volatile alcohol solvent may be achieved simply and efficiently. Penetration of the dyebath is greatly increased by our novel process and, since no washdown in shade is effected by the scouring, greatly increased color value is achieved. Thus,'consid i erably less dyestufi" need be employed'to attain .desirably deep shades. Furthermore, the dyeing is extremely even and level and mottled effects in fabrics containing spun yarns of cellulose acetate or other organic derivative of cellulose are entirely eliminated. The lower aliphatic alcohols which, are'suitable, for use in forming the solvent dyebathswhlcli we employ for the pad-dyeing operationare'those alcohols which are solvents for the dyestuffs em secondary amyl alcohol and tertiary amyl alcohol,

or mixture of these alcohols may also be used: Optimum results are obtained.- when the lower aliphatic alcohol employedls ethyl alcohol and V the latter comprises at least 95% by weight of the solvent medium of the dyebath.

Various dyestuffs for the cellulose acetate or organic derivative of cellulose materials may'be employed in accordance withournovel process. These dyestuiTs may be acid dyesi which areordinarily used for the dyeing of wool and-which .do not possess any substantial affinity for organic derivative of cellulose materials when applied by the methods usually employed for, applying said acid dyestuffs; as well asthose dyes which are relatively insoluble'in waterand which are usuallyapplied-to organic acid ester of cellulose mati'ials in the rem of'aqueou's dispersions. Mixtiires or'these dyestulis may also be employed.

'I'he amount'or dyestuff' dissolved in the dyebatliwilli ofcourse, varywith the final shade desired the material which is being .dyed and may be from as low as 0.1% up to 5% based on tlie-*weigl'it of the materialto be dyed. Thus, as

a continuous process, the scoured fabric may be unwound" from a roll, passedthrough a solution 01 tlie'" dye'stiiif, the'n between nipping rolls of 2. padding manjgle whichare adjusted to permit the desired amount of dye-liquor to be retained in the'fabric; and" the fabric then passed over skying rolls to allow it to dry prior to washing with wa tri The duration of the immersion of the refine the alcoholdyeb'ath is relatively short and maybe from 1 to"3O seconds. If desired, tnevfabric-may be proc'essed through the padding mangle at speedsranging up to "70' yards per minute;

"Fabrics dyed in accordance with our novel process mayli'ave'a' basis of yarns of cellulose acetateor other organic" derivative of cellulose. Examples ofother organic derivatives of celluless-are cellulose" ester's such as cellulose propioii cellulose butyrate; cellulose acetate-propioand? cellulose acetate-butyrate, as well as delliilo'se -ethers suchasethyl'cellulo'se and benzyl cellulose.

In order further t'o=- illustrate our invention, bilt withoutbeing limited thereto, the following example is given:

propylainino anthraquinone 0.31 l nretliylamino-arithraquinone* 0.03 2 chlor-4 nitro 6 brom benzene-azo-dihydroxyethyl meta-chlor-aniline 0.49

Thedyed iabric. is-allowedto dry substantially by evaporating the alcohol therefrom before being batched up. The dyed: fabric is then rinsed in water bybeingpassedthrough a washz box or on a jig for four ends, dried and finished. A fabric dyed in a level, even medium tan shade is obtained which is entirely free of mottled efiects. The color value of the dyed fabric is practically double that experienced with prior dyeing methods,thus permitting deeper shadestto be obtained with the same amount of dyestufi" or equivalent shades to be dyed with a substantial reduction in the amount of dyestufi" employed in the dyebath;

Thesterm dyestufi as employed in the claims in: the expressions a dyestufi for the organic derivative of cellulose material and a dyestuff for thecellulose acetate material is to be construed as. meaning, an acid dyestuii ordinarily used for the dyeing of wool and which does not possess any substantial affinity for organic derivative of cellulose, such as cellulose acetate, materials when applied by the methods usually employed for applying said acid dyestuffs, or a dyestufif which is relatively insoluble. in water and which is usually applied to organic derivative of cellulose materials in the form of an aqueous dispersion or a mixture of such dyestuifs.

It is to be understood that the foregoing detailed description is given merelyv by way of. illustration and'that many'variationsma'y be made therein without departing from the spirit of our invention.

Having described our invention, what we desire to secure by Letters Patent is:

1. Process forthecoloration of textilematerials containing spun yarns of stable fibers having a, basis Of an organic derivative of cellulose, which comprises. padding said textile materials with a dyebath consistingof, as the sole components, a (lyestuff. for the textile material dissolved in a concentrated lower aliphatic alcohol containing from 0 to5% by weight of water, skying the dyed textile material until dry without anintermediate washing step, and then rinsing the dry textile material in water. a v v 2. Processv for the coloration of. textile materials containing spun yarns of staple fibers. having a basis of cellulose. acetate, which comprises padding said textile materials with :a dyebath consisting of, as the sole components, a dyestulf for the textile material dissolved in a concentrated lower aliphatic alcohol containing from 0 to-5% by weight of water, skying the dyed textile material until dry without: an intermediate washing step,.and then rinsing the dry textile material in water. a

3. Process forthe coloration of textile materials containing spun yarns of staple fibers having a basis of cellulose acetate, which comprises padding, said textile materials with a. dyebath consisting of, as the sole components, a dyestufi for the textile material dissolved in ethyl alcohol containing from 0 to 5% by weight of water, skying the dyedtextile material until dry without an intermediate Washing. step, and then rinsing the dry textile material inwater.

4. Process for the colorationof textile materials containing. spun. yarns of staple fibers having a basis of cellulosev acetate, which comprises padding. said textile materials with a dyebath consisting of, as the sole components, a dyestufi for the textile material dissolved in butyl alcohol containing from O-to 5% by weight of water, skying the dyed textile material until dry without an intermediate washing step, and then rinsing the dry textile material in water.

5.. Process for the coloration of textile materials containing. spun: yarns-ofstaple fibers having a basis of cellulose acetate, which comprises padding said textile materials with a dyebath consisting of, as the sole components, a dyestufi for the textile material dissolved in propyl alcohol containing from 0 to 5% by weight of water, skying the dyed textile material until dry without an intermediate Washing step, and then rinsing the dry textile material in water.

WILFRED T. NORMAND.

WILLIAM J. CRAMER, JR.

REFERENCES CITED The following references are of record in the file of this patent:

Number Number 6 UNITED STATES PATENTS Name Date Whitehead Dec. 10, 1929 Croft Mar. 28, 1944 Wesson Sept. 4, 1945 FOREIGN PATENTS Country Date Great Britain July 4, 1929 Great Britain Oct. 13, 1940 

1. PROCESS FOR THE COLORATION OF TEXTILE MATERIALS CONTAINING SPUN YARNS OF STABLE FIBERS HAVING A BASIS OF AN ORGANIC DERIVATIVE OF CELLULOSE, WHICH COMPRISES PADDING SAID TEXTILE MATERIALS WITH A DYEBATH CONSISTING OF, AS THE SOLE COMPONENTS, A DYESTUFF FOR THE TEXTILE MATERIAL DISSOLVED IN A CONCENTRATED LOWER ALIPHATIC ALCOHOL CONTAINING FROM 0 TO 5% BY WEIGHT OF WATER, SKYING THE DYED TEXTILE MATERIAL UNTIL DRY WITHOUT AN INTERMEDIATE WASHING STEP, AND THEN RINSING THE DRY TEXTILE MATERIAL IN WATER. 